Batch rendering of 10,000 images from 10,000 obj files
This script will take all OBJ files in a certain directory, and one by one load them, render them, and remove them from the scene again.  This way you can render 10000 OBJ files without having to load them all into memory at the same time. The OBJ files do not need to be named in any special way (except ending in .obj).

import bpy
import pathlib

# Adjust this for where you have the OBJ files.
obj_root = pathlib.Path('c:/temp/obj')

# Before we start, make sure nothing is selected. The importer will select
# imported objects, which allows us to delete them after rendering.
bpy.ops.object.select_all(action='DESELECT')
render = bpy.context.scene.render

for obj_fname in obj_root.glob('*.obj'):
    bpy.ops.import_scene.obj(filepath=str(obj_fname))

    render.filepath = '//obj-%s' % obj_fname.stem
    bpy.ops.render.render(write_still=True)

    # Remember which meshes were just imported
    meshes_to_remove = []
    for ob in bpy.context.selected_objects:
        meshes_to_remove.append(ob.data)

    bpy.ops.object.delete()

    # Remove the meshes from memory too
    for mesh in meshes_to_remove:
        bpy.data.meshes.remove(mesh)


The rendered image files will have the OBJ filename in their name, so if you have cube.obj, the output file will be obj-cube.jpg (assuming you're rendering to JPEG files).

The camera and lighting is use as-is in the scene, so you can set it up beforehand and render everything with the same settings.

NOTE: since this is a synchronous script, Blender's UI will block while it's running. You may want to start Blender from a terminal (or choose Window > Toggle System Console on Windows) before you start it, to keep an eye on its progress.